#ifndef __LOGGER_H__
#define __LOGGER_H__
/*
    完成日志器模块
    1.抽象日志器基类
    2.派生出日志器子类（同步日志器类& 异步日志器类）
*/
// #define _GNU_SOURCE

#include <atomic>
#include <mutex>
#include <unordered_map>
#include <cstdarg>

#include "Util.hpp"
#include "level.hpp"
#include "format.hpp"
#include "sink.hpp"
#include "looper.hpp"
#include "buffer.hpp"

namespace bin
{
    class Logger
    {
    public:
        using ptr = std::shared_ptr<Logger>;

        Logger(const std::string &logger_name, LogLevel::value level, Formatter::ptr &Formatter, std::vector<LogSink::ptr> &sinks)
            : _logger_name(logger_name), _limit_level(level), _formatter(Formatter), _sinks(sinks.begin(), sinks.end())
        {
        }

        const std::string &name()
        {
            return _logger_name;
        }

        // 完成构造日志消息对象过程并进行格式化，得到格式化后的日志消息字符串，并进行落地输出
        void debug(const std::string &file, size_t line, const std::string &fmt, ...)
        {
            // 1.判断当前的日志是否达到了输出等级
            if (LogLevel::value::DEBUG < _limit_level)
                return;

            // 2.对fmt格式化字符串和不定参进行字符串组织，得到消息字符串
            va_list ap;
            va_start(ap, fmt);
            char *res;
            int ret = vasprintf(&res, fmt.c_str(), ap); // 申请一块空间，把数据放到空间中，再把这块空间的地址赋值给res
            if (ret == -1)
            {
                std::cerr << "vasprintf failed\n";
                return;
            }
            va_end(ap);
            serialize(LogLevel::value::DEBUG, file, line, res);
            free(res);
        }
        void info(const std::string &file, size_t line, const std::string &fmt, ...)
        {
            // 1.判断当前的日志是否达到了输出等级
            if (LogLevel::value::INFO < _limit_level)
                return;

            // 2.对fmt格式化字符串和不定参进行字符串组织，得到消息字符串
            va_list ap;
            va_start(ap, fmt);
            char *res;
            int ret = vasprintf(&res, fmt.c_str(), ap); // 申请一块空间，把数据放到空间中，再把这块空间的地址赋值给res
            if (ret == -1)
            {
                std::cerr << "vasprintf failed\n";
                return;
            }
            va_end(ap);
            serialize(LogLevel::value::INFO, file, line, res);
            free(res);
        }
        void warn(const std::string &file, size_t line, const std::string &fmt, ...)
        {
            // 1.判断当前的日志是否达到了输出等级
            if (LogLevel::value::WARN < _limit_level)
                return;

            // 2.对fmt格式化字符串和不定参进行字符串组织，得到消息字符串
            va_list ap;
            va_start(ap, fmt);
            char *res;
            int ret = vasprintf(&res, fmt.c_str(), ap); // 申请一块空间，把数据放到空间中，再把这块空间的地址赋值给res
            if (ret == -1)
            {
                std::cerr << "vasprintf failed\n";
                return;
            }
            va_end(ap);
            serialize(LogLevel::value::WARN, file, line, res);
            free(res);
        }
        void error(const std::string &file, size_t line, const std::string &fmt, ...)
        {
            // 1.判断当前的日志是否达到了输出等级
            if (LogLevel::value::ERROR < _limit_level)
                return;

            // 2.对fmt格式化字符串和不定参进行字符串组织，得到消息字符串
            va_list ap;
            va_start(ap, fmt);
            char *res;
            int ret = vasprintf(&res, fmt.c_str(), ap); // 申请一块空间，把数据放到空间中，再把这块空间的地址赋值给res
            if (ret == -1)
            {
                std::cerr << "vasprintf failed\n";
                return;
            }
            va_end(ap);
            serialize(LogLevel::value::ERROR, file, line, res);
            free(res);
        }
        void fatal(const std::string &file, size_t line, const std::string &fmt, ...)
        {
            // 1.判断当前的日志是否达到了输出等级
            if (LogLevel::value::FATAL < _limit_level)
                return;

            // 2.对fmt格式化字符串和不定参进行字符串组织，得到消息字符串
            va_list ap;
            va_start(ap, fmt);
            char *res;
            int ret = vasprintf(&res, fmt.c_str(), ap); // 申请一块空间，把数据放到空间中，再把这块空间的地址赋值给res
            if (ret == -1)
            {
                std::cerr << "vasprintf failed\n";
                return;
            }
            va_end(ap);
            serialize(LogLevel::value::FATAL, file, line, res);
            free(res);
        }

    protected:
        void serialize(LogLevel::value level, const std::string &file, size_t line, char *str)
        {
            // 3.构造LogMsg对象
            LogMsg msg(level, line, file, _logger_name, str);

            // 4.通过格式化工具对LogMsg进行格式化，得到格式化之后的日志字符串
            std::stringstream ss;
            _formatter->format(ss, msg);

            // 5.进行日志落地
            log(ss.str().c_str(), ss.str().size());
        }
        // 抽象接口完成实际的落地输出--不同的日志器会有不同的实际落地方式
        virtual void log(const char *data, size_t len) = 0;

    protected:
        std::mutex _mutex;
        std::string _logger_name;
        std::atomic<LogLevel::value> _limit_level;
        Formatter::ptr _formatter;
        std::vector<LogSink::ptr> _sinks;
    };

    // 同步日志器
    class SyncLogger : public Logger
    {
    public:
        SyncLogger(const std::string &logger_name, LogLevel::value level, Formatter::ptr &Formatter, std::vector<LogSink::ptr> &sinks)
            : Logger(logger_name, level, Formatter, sinks)
        {
        }

    protected:
        void log(const char *data, size_t len)
        {
            std::unique_lock<std::mutex> lock(_mutex);
            if (_sinks.empty())
                return;
            for (auto &sink : _sinks)
            {
                sink->log(data, len);
            }
        }
    };

    // 异步日志器
    class AsyncLogger : public Logger
    {
    public:
        AsyncLogger(const std::string &logger_name, LogLevel::value level, Formatter::ptr &formatter, std::vector<LogSink::ptr> &sinks, AsyncType looper_type)
            : Logger(logger_name, level, formatter, sinks)
              // 参数绑定
              ,
              _looper(std::make_shared<AsyncLooper>(std::bind(&AsyncLogger::realLog, this, std::placeholders::_1), looper_type))
        {
        }

        // 将数据写入缓冲区
        void log(const char *data, size_t len)
        {
            _looper->push(data, len);
        }

        // 设计一个实际落地函数，将缓冲区中的数据落地
        void realLog(Buffer &buf)
        {
            if (_sinks.empty())
                return;

            for (auto &sink : _sinks)
            {
                sink->log(buf.begin(), buf.readAbleSize());
            }
        }

    private:
        AsyncLooper::ptr _looper;
    };

    // 使用建造者模式来建造日志器，而不要让用户直接去构造日志器，简化用户的使用复杂度
    // 1.抽象一个日志器建造者类
    //   1.设置日志器类型
    //   2.将不同类型日志器的创建放到同一个日志器建造者类中完成
    // 2.派生出具体的建造者类
    //   1.局部日志器的建造者 & 全局的日志器建造者

    enum class LoggerType
    {
        LOGGER_SYNC,
        LOGGER_ASYNC
    };

    class LoggerBuilder
    {
    public:
        LoggerBuilder()
            : _logger_type(LoggerType::LOGGER_SYNC), _limit_level(LogLevel::value::DEBUG), _looper_type(AsyncType::ASYNC_SAFE)
        {
        }

        void buildLoggerType(LoggerType type)
        {
            _logger_type = type;
        }

        void buildEnableUnSafeAsync()
        {
            _looper_type = AsyncType::ASUNC_UNSAFE;
        }

        void buildLoggerName(const std::string &name)
        {
            _logger_name = name;
        }
        void buildLoggerLevel(LogLevel::value level)
        {
            _limit_level = level;
        }
        void buildFormatter(const std::string &pattern)
        {
            _formatter = std::make_shared<Formatter>(pattern);
        }

        template <class SinkType, class ...Args>
        void buildSink(Args &&...args)
        {
            LogSink::ptr psink = SinkFactory::create<SinkType>(std::forward<Args>(args)...);
            _sinks.push_back(psink);
        }

        virtual Logger::ptr build() = 0;

    protected:
        AsyncType _looper_type;
        LoggerType _logger_type;
        std::string _logger_name;
        std::atomic<LogLevel::value> _limit_level;
        Formatter::ptr _formatter;
        std::vector<LogSink::ptr> _sinks;
    };

    class LocalLoggerBuilder : public LoggerBuilder
    {
    public:
        Logger::ptr build() override
        {
            assert(!_logger_name.empty()); // 必须要有日志器名称
            if (_formatter.get() == nullptr)
            {
                _formatter = std::make_shared<Formatter>();
            }
            if (_sinks.empty())
            {
                buildSink<StdoutSink>();
            }
            if (_logger_type == LoggerType::LOGGER_ASYNC)
            {
                return std::make_shared<AsyncLogger>(_logger_name, _limit_level, _formatter, _sinks, _looper_type);
            }

            return std::make_shared<SyncLogger>(_logger_name, _limit_level, _formatter, _sinks);
        }
    };

    class LoggerManager
    {
    public:
        static LoggerManager &getInstance()
        {
            // 在C++11后，针对静态局部变量，编译器在编译的层面实现了线程安全
            // 当静态局部变量在没有构造完成之前，其他线程进入就会进入阻塞
            static LoggerManager eton;
            return eton;
        }

        void addLogger(Logger::ptr &logger)
        {
            if(hasLogger(logger->name()))
                return;
            std::unique_lock<std::mutex> lock(_mutex);
            _loggers.insert(std::make_pair(logger->name(), logger));
        }

        bool hasLogger(const std::string &name)
        {
            std::unique_lock<std::mutex> lock(_mutex);
            auto it = _loggers.find(name);
            if(it == _loggers.end())
                return false;
            return true;
        }

        Logger::ptr getLogger(const std::string &name)
        {
            std::unique_lock<std::mutex> lock(_mutex);
            auto it = _loggers.find(name);
            if(it == _loggers.end())
                return Logger::ptr();
            return it->second;
        }

        Logger::ptr rootLogger()
        {
            return _root_logger;
        }

    private:
        LoggerManager()
        {
            std::unique_ptr<bin::LoggerBuilder> builder(new bin::LocalLoggerBuilder());
            builder->buildLoggerName("root");
            _root_logger = builder->build();
            _loggers.insert(std::make_pair("root", _root_logger));
        }

    private:
        std::mutex _mutex;
        Logger::ptr _root_logger; // 默认日志器
        std::unordered_map<std::string, Logger::ptr> _loggers;
    };


    //设计一个全局日志器的建造者--在局部的基础上，增加了一个功能：将日志器添加到单例对象中
    class GlobalLoggerBuilder : public LoggerBuilder
    {
    public:
        Logger::ptr build() override
        {
            assert(!_logger_name.empty()); // 必须要有日志器名称
            if (_formatter.get() == nullptr)
            {
                _formatter = std::make_shared<Formatter>();
            }
            if (_sinks.empty())
            {
                buildSink<StdoutSink>();
            }

            Logger::ptr logger;
            if (_logger_type == LoggerType::LOGGER_ASYNC)
                logger = std::make_shared<AsyncLogger>(_logger_name, _limit_level, _formatter, _sinks, _looper_type);
            
            else
                logger = std::make_shared<SyncLogger>(_logger_name, _limit_level, _formatter, _sinks);

            LoggerManager::getInstance().addLogger(logger);
            return logger;
        }
    };
}

#endif